Production of hydrocarbons from loose, unconsolidated, and/or fractured formations often produces large volumes of particulates along with the formation fluids. These particulates can cause a variety of problems. For this reason, operators use stand-alone screens (or screens together with gravel packing of the screens) in the wellbore annulus as a common technique for controlling the production of such particulates. Fracturing the formation and using the screen to retain the frac sand as well as secondary sand retention is also a common technique.
To gravel pack a completion, a screen is lowered on a workstring into the wellbore and is placed adjacent the subterranean formation. Particulate material, collectively referred to as “gravel,” and a carrier fluid are pumped as a slurry down the workstring. Eventually, the slurry can exit through a “cross-over” into the wellbore annulus formed between the screen and the wellbore.
The carrier liquid in the slurry normally flows into the formation and/or through the screen itself. However, the screen is sized to prevent the gravel from flowing through the screen. This results in the gravel being deposited in the annulus between the screen and the wellbore to form a gravel-pack around the screen. The gravel, in turn, is sized so that it forms a permeable mass that allows produced fluids to flow through the mass and into the screen but blocks the flow of particulates into the screen.
Other than wellscreens, downhole assemblies can use slotted or perforated liners, perforated tubulars, and other permeable well components. For example, a permeable mechanical tube is used to provide a continuous wellbore for produced well fluids in reservoirs with competent sand control. At times, operators desire to install or run in hole these types of permeable well components in an impermeable manner so that flow in/out of the component is prevented and pressure may be applied as part of fluid circulation or as required to initiate and terminate certain downhole operations.
Various techniques have been used to make such permeable well components be impermeable for run-in. In one technique, plugging is done on the permeable well component using wax, polymeric coatings, or dissolvable materials. After the plugged well component is run in hole, a reactive fluid is placed in or around the component, and the fluid reacts with the plugging material to unplug the component and make it permeable. For example, the reactive liquid is circulated to dissolve or otherwise make the component permeable and allow wellbore fluid to pass into the component and up the well.
Some general examples of approaches for temporary plugging components are disclosed in U.S. Pat. No. 6,394,185; U.S. Pat. No. 7,360,593; U.S. Pat. No. 7,762,342; U.S. Pat. No. 8,342,240; U.S. Pat. No. 8,430,174; and U.S. Pat. No. 8,490,690. For example, U.S. Pat. No. 8,490,690 discloses a wellscreen having plugs in the basepipe so that flow from the screen and drainage layer cannot enter the basepipe. An acid containing structure is positioned in the basepipe or in the drainage layer of the screen. When the structure is contacted by an aqueous fluid, flow through the sidewall of the wellscreen can be selectively permitted as the structure releases acid that dissolves the plugs.
For example, U.S. Pat. No. 7,360,593 discloses coating for a wellscreen that protects the screen from damage as it is inserted into the wellbore. Once in the well, released reactive material reacts with and degrades any potential plugging materials that may have accumulated, such as drill solids, filter cake, additives, drilling fluids, etc. The reactive material melts or dissolves a binder of the coatings.
Although the techniques for temporarily plugging a permeable well component may be effective in some cases, the problem is creating a cost effective well component that functions suitably in an impermeable state to provide the necessary mechanical properties and then in a permeable state to offer high-permeability and low pressure drop through the component for operations and use.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.